jroosh

Is the IS really that powerful that snow tires would break loose on the highway at 50-60 MPH on dry (but salty) roads going straight ahead?

I got my new snows today and kicked it a little at highway speed and the traction control indicator came on and I felt a slight bit of slippage in the rear.

I called my tire guy and he said to lower the air pressure from 42 PSI to 35 which seemed to soften the ride a bit but I can still break it (slightly) loose at highway speeds.

Otherwise winter tires make a huge difference. The car was almost worthless for traction in any kind of snow with the Z-rated Potenzas. Now it even bites into ice (relatively speaking) and definitely snow.

Toyo Observe 215/45/17

Opinions welcomed.

Riceboy77

I don't think it's so much the power as it is the type of tires you switched to. The car is only going to be as good as the tires can perform, and winter tires aren't made to drive with high performance at super-high speeds. Check the speed rating on your tires and see what their limit is. I got the Toyo Garrit HT's and although they're decent on the highway, I wouldn't drive as I do in the summer with them.

jroosh

I agree. I just didn't expect the TRAC to be so sensitive. The Toyo Observe is H-Rated.

jroosh

I have figured out why this is happening...

I chose to put 215/45R17 winter tires on my stock 17" wheels. They are special order and are very wide, just like the summer tires.

Tires that wide, even if they are winter tires, are going to be more prone to some slippage by the virtue of how much torque the IS has.

I might have gotten 16" wheels and winter tires given the chance to do it over but overall I like the look of the 17" wheels year round much better. The overall cost is lower and the downside of the 17" snows is slight anyway.

Generic

Whoa, you have them at 42PSI?? Isn't that like the Maximum pressure rating for them?

You want to keep your tires, regardless of size at the same pressure as stock, or near stock depending on your driving style. I'd guess that stock pressure is from 30-35 PSI, so you'd want your winter tires at that same pressure.

Murdock

jroosh

Thank you, and you are correct - that is max pressure. My tire guy likes to run tires at higher pressure, but I backed the pressure down to 35 PSI the very same day.

soyb0mb

For your next set of snows, you might want to give the Michelin Alpin Pilots a test... they handle great int he dry, but are a legit snow tire for when you need them.
I ahve a set and love 'em!

Michael S. Doma

Something similar happens on my new Bridgestone 17 inch snow tires. When taking off from a toll booth at a fairly brisk (but not WOT) pace with Traction control on (I usually switch it off) The slippage/skidding indicator comes on (looks kind of cool) . It does not happen at highway speeds no matter how hard I stomp on the gas maybe it is the oil spills at the toll booths affecting traction, but I never noticed it with my regular tires. Guess I need that turbo after all to spin those tires at 55mph+.